A microprocessor typically includes a cache memory for storing copies of the most recently used memory locations. The cache memory generally is smaller and faster than main memory (e.g., disk). A microprocessor also typically includes an instruction prefetch unit that is responsible for prefetching instructions for a CPU (Central Processing Unit). In particular, an instruction cache unit is typically organized in a way that reduces the amount of time spent transferring instructions having a power of two size into the prefetch unit. For example, a 256-bit bus (256 bits=4.times.8 bytes=32 bytes) connecting the instruction cache unit and the prefetch unit allows a 32-byte instruction prefetch unit to fetch 32 bytes of instruction data in a single cycle of the microprocessor.